Unnamed aerial vehicles (UAVs) are of great importance on various platforms because of its rapid and easy deployment. In order to get an insight of UAV aided communication systems, an accurate channel model of UAV channels is needed. We propose a general channel model for UAV link based on alpha-betamodel, which is extensively used in the literature. Specifically, we derive the normalized expression of probability density function (PDF), cumulative distribution function (CDF), and moments of the proposed model. Shadowing component is assumed to follow log-normal distribution and multipath component is characterized with the help of Nakagami-m distribution. The outage probability of a UAV based communication system is also obtained by using CDF expression.